Uncontrolled hemorrhage contributes the main cause of syndrome after injuries in many circumstances, which is a threat to human life. Meanwhile, rapid and effective hemostasis is an important part of clinical surgery and first aid in the filed. According to a crude investigation, approximately 500 tons of hemostats are used in clinical every year in China. Therefore, an effective hemostatic material for prompt hemorrhage-arresting and wound healing in hospital and in field is eagerly needed all over the world.
Up to the present, traditional hemostatic materials include first-aid kits, tourniquets, bandages and the sterilized dressings that can be used to compensate the first-aid kit in a hemostatic treatment. However, these hemostatic materials have been found to have the shortcomings such as being less effective in combined injuries, multiple injuries and wounds with a large injury area, and not so ready-to-use as desired for a first aid in field.
In order to overcome these shortcomings, a series of novel hemostatic materials have been developed and used in clinical applications in recent years. Based on the main components, these new hemostatic materials can be classified into Fibrin Glues (FG), Oxidized Celluloses (OC), Oxidized regenerated celluloses (ORC) and mineral zeolite-based hemostats. The Fibrin Glues exhibit effective hemostatic property, good adhesion and good biocompatibility. The accepted hemostatic mechanism with these materials is to mimic the spontaneous coagulation process, while being independent of platelets and coagulation factors, which makes them especially effective in halting bleeding in organs suffering coagulation dysfunction. Since Tisseel/TiSSUCOI fibrin glues (manufactured by Immuno AG Co., Austria) being approved by FDA in 1998, more of these materials have been rapidly developed. To date, the commercially available fibrin-based glue products include Beriplast P, Hemaseel, Biocol, Boheal and Quixil, etc. As for the oxidized cellulose and oxidized regenerated cellulose, these materials have good degradable, antibacterial and hemostatic properties, and are especially effective to arrest slow bleeding. At present, the examples of commercially available OC and ORC hemostats include the Oxycel series and the Surgicel series. The hemostatic mechanism with these materials is proposed to be that the acidic carboxyl group in the molecule binds with the Fe3+ ion in the hemoglobin to generate the acidic Fe3+-hemin in blood, whereby red-brown gel blocks are formed to close the end of capillaries, and then to arrest the bleeding. Inert mineral zeolite particles were first found to have a good hemostatic effect by Francis X. Hursey in 1980s, and was patented as U.S. Pat. No. 4,822,349 in 1989. In 2002, Z-Medica Corporation produced a type of new hemostatic materials under the named of QuikClot™. These materials have been approved by FDA and commercially available. It has been shown that these zeolite-based materials are superior to other hemostatic materials in both hemostatic efficacy and survival rate. The hemostatic mechanism of these mineral zeolites mainly resides in their extraordinary selective adsorption of water relative to erythrocyte, platelet and other coagulation factors, which leads to a quick hemostasis by concentrating the clotting factors at the injury site. As a further improvement, CN1727011A designed and developed a mesoporous zeolite hemostatic agent. Due to the unique mesoporous structure and tunable pore size, the mesoporous zeolite could stop bleeding more efficiently and more quickly. And, the new agent could further improve therapeutic effects by adsorbing antibiotics or analgesics on the material. In view of these, mesoporous molecular sieves have a broader market prospects than the traditional zeolite hemostats.
Although these new hemostatic agents, to some extent, have overcome some shortcomings of the traditional hemostatic materials, and are useful in certain clinical applications, they still have some significant drawbacks. For instance, Fibrin Glues have been blamed of a high production cost, the risk of causing blood-borne diseases and infections in human beings and animals, the complicated procedure of application, being slow in arresting bleeding and less effective in arresting bleeding of large blood vessels. The oxidized cellulose and oxidized regenerated celluloses have been reported to incline to adsorb blood and then expand, which may cause neurothlipsis. For mineral zeolite hemostats, they may generate residues in the tissue as “foreign bodies”, because they are not biodegradable. And, the mineral zeolite hemostats become exothermal on adsorbing moisture, which may burn the tissue when being used in a massive bleeding wound.